Add a "fork" of musl as //fusl.

fusl/src/passwd/getgrent_a.c

+#include "pwf.h"
+#include <pthread.h>
+
+static unsigned atou(char **s)
+{
+        unsigned x;
+        for (x=0; **s-'0'<10U; ++*s) x=10*x+(**s-'0');
+        return x;
+}
+
+int __getgrent_a(FILE *f, struct group *gr, char **line, size_t *size, char ***mem, size_t *nmem, struct group **res)
+{
+        ssize_t l;
+        char *s, *mems;
+        size_t i;
+        int rv = 0;
+        int cs;
+        pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
+        for (;;) {
+                if ((l=getline(line, size, f)) < 0) {
+                        rv = ferror(f) ? errno : 0;
+                        free(*line);
+                        *line = 0;
+                        gr = 0;
+                        goto end;
+                }
+                line[0][l-1] = 0;
+
+                s = line[0];
+                gr->gr_name = s++;
+                if (!(s = strchr(s, ':'))) continue;
+
+                *s++ = 0; gr->gr_passwd = s;
+                if (!(s = strchr(s, ':'))) continue;
+
+                *s++ = 0; gr->gr_gid = atou(&s);
+                if (*s != ':') continue;
+
+                *s++ = 0; mems = s;
+                break;
+        }
+
+        for (*nmem=!!*s; *s; s++)
+                if (*s==',') ++*nmem;
+        free(*mem);
+        *mem = calloc(sizeof(char *), *nmem+1);
+        if (!*mem) {
+                rv = errno;
+                free(*line);
+                *line = 0;
+                gr = 0;
+                goto end;
+        }
+        if (*mems) {
+                mem[0][0] = mems;
+                for (s=mems, i=0; *s; s++)
+                        if (*s==',') *s++ = 0, mem[0][++i] = s;
+                mem[0][++i] = 0;
+        } else {
+                mem[0][0] = 0;
+        }
+        gr->gr_mem = *mem;
+end:
+        pthread_setcancelstate(cs, 0);
+        *res = gr;
+        if(rv) errno = rv;
+        return rv;
+}